Comparaison between dry and wet anaerobic fermentation process of dairy cattle manure under different temperatures

الملخص

The anaerobic batch fermentation of undiluted (dry) dairy cattle manure under psychrophilic, mesophilic and thermophilic conditions was studied to establish its biodegradability and compare the feasibility with conventional process (diluted manure). The biodegradability of undiluted manure was 0.5%, 11.5%, 30.7%, 44.9% and 1.1% as compared with 0.4%, 10.2%, 32.5%, 53.1% and 32.4% observed for the diluted manare at 15°C, 25°C, 35°C, 45°C and 55°C temperatures, respectively. The low biodegradability    (P<0,05)  of undiluted manare at 55°C temperature was due to process failure. The process failure occurred because of excessive washout of carbon dioxide during initial phase of fermentation resulting in drop in pH below the toxic limit of 6.0. The study suggests that dry anaerobic fermentation process may be a promising alternative to the conventional process in mesophilic temperature conditions.